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Jan. 6, 1931. w. D. LA RUE SOUND REPRODUCING MECHANISM Filed May 1, 19

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SOUND REPRODUCING MECHANISM Filed May 1, 1926 1 Z S h'ee'ts-Sheet 2 r a 1E 19 1 Patented Jan. 6, 1931 f WILLIAM D;

LA aUE, or PHILADELPHIA, 'PENIiSiZLVANIAQASSIGNOR r VICTOR TALK- meivreonmn COMPANY; A coeronaa'ion or {New JERSEY sounnizijraonucmennormmsm l r mamas filed m 1,

This invention relates to mechanism for converting mechanical vibrations into acoustical vibrations, andparticularly :to mech-' anism of this'character for use iii-sound reproducing machines, but while the invention will be hereinafter described in connection with its embodiment in devices for reproducing sound from sound records of any suitable character, itis to be expressly understood that the invention is not restricted thereto; as. it

is susceptible ofembodiment in devices for a generating amplified sound waves-where the a source of vibrations to be converted into acoustical waves is other than a record of sound. i v

Heretofore, sound reproducing machines have generally employed some form of'liorn for amplifying the soundvgenerated bythe vibration of a diaphragm that is operated by a stylus cooperating with a record trace. But

a horn, even of simple character. introduces many complexities and difficulties-into the securing of faithfulisound reproduction, be-

cause of theacoustical laws underlying the operation of a confined body of air in transmitting and amplifying sounch while-the necessity of so shaping the horn that it may have theproperlength and cross sectional size while confining itwithin the space of a comm'ercially practicable structure hasvgrea-tly increased these complexities and difiiculties.

It has heretofore been proposed to avoid the use of a horn by reproducing the sound directly from a diaphragm ofvsuch area that the volume of air placed in vibration will give the desiredvolume of -soundbut proposals ofthis' character have introduced other complexities and difiiculties that have ,ren-

dered them impracticable for the mostpart;

If a large diaphragm is somounted that'it is closely adjacent to the stylus and moves therewith over the record tablet, the burden imposed on the stylus of both vibrating such a diaphragm and feeding it relativelyitothe recordfltablet has not only tended tofwear the record trace very.rapidlmb'ut' has also intro duced other difficulties andproblems wmch have militated against faithful sound reproduction. If the diaphragm is mounted at a distance'fi-om the'stylus so as to take theburlong column; of liquid and the attendant 192 Serial 166,073.

den off of th'e stylus the introductionof a 'sufiicientlyrigid unechanism between the stylus and the-diaphragm to transmit the vibrations from-the stylus to the diaphragm with undiminis h'ed amplitude and power has introduced grave ldifliculties and problems because of the added weight, the inertia effects of the relatively heavy vibrating parts,

the naturallperiods f vibration of the ele- -ments,-etc.

an object of'this invention to provide a method I and apparatus a for reproducing sound vibrations which avoidthe necessity of a horn and which enablethe use of a large diaphragm Without introd'ucingthe difficulties heretofore encountered whether the dia.

phragm be positioned close to or remote from the stylus" f It has alsobeen proposed heretofore to transmitthevibrations generated by a stylus V :coope-rating w th a record trace to a point relatively remote from'said-stylus by means of interposedfcolumn of fluid. Devicesof ,tlllS character heretofore proposed,; however,

have generally einploye'da liquid as the mediuni ffortransmitting the pressures generated by the vibration of the diaphragm, and devices of-th s character have proven neither feasible nor satisfactory v for a variety of reason amongqwhrchmay be noted the diflil'lill') in maintaining fluid-tight, joints, particulzfirly in constructions which must provide for relative movement between the stylus and the recordtra'ce {the Weight of a relativeincreasedpressure and weary-on the record.

trace [the relative rigidity of a; column of liquidowing to itsin'con' pressible character; sojthat: the diaphragm at the remote end of the columnanay, react on the diaphragm at the stylus-end of the column insubstantially them-me ay as if a rigid bar extended be-' tween the two idia'phr'agms. Some efforts havealsobeen niadeto use a column of gaseous-fluid for transmitting pressuresjfrom a stylus op'erated diaphragm to a diaphragm relatively remote therefrom. But in none of the structures heretofore proposed. has: the

fipri'nciple of 1 transmitting the variable pres sures and converting them into acoustic v ibrations been such as to enable an eflicient' and faithful transmission of the vibrations under conditions which permit a' desired volume of sound to. be generated from arelatively large diaphragnrivitliout the u se'of an amplifier operating upon the horn or megaphone principle.

It is an object of this invention to provide a method and. apparatus for transmitting sound vibrations by a fluid column to a' dis ,tance from the source ofvibrations vvhile avoiding the various dlfiieulties incident to the use of a liquid column.

Another object of this invention is to pro- Another object of this invention is to proide a method and" apparatus for reproducing sound vibrations 'Whereby sounds 0f the desired volume" may be radiated from a large diaphragm at'any suitable distance from the "source of vibrations vvrthoutsubstantml loss of energy and "without substantial distortion ofthe" vibrations in the transmission of the vibrationsto said diaphragm. 1

Another object of this invention is to provide' a method and apparatus'for reproduc ing sound vibrations Whereby'alarge diaphragm positioned relatively/remote from the source of vibrations maybe effective in faithfully reproducing sounds of low periodicity as Well as sounds of'higher periodicity;

Another object of this invention isto provide a method and apparatus for reproducing sound vibrationswhereby the sound vibrations may beradiated from a relatively large diaphragm at a distance from the "source of vibrations ithout'introducing deleterious efiec'ts arising from-the natural-periods of vibrations of the sound transmitting elements.

' 'Another object of this invention'is to provide'a methodand apparatus for reproducing sound vibrations whereby a large diaphragm maybe"positioned at a fldistance from the "source of vibrations Withoutintroducing the inertia effects of-relatively heavy or relative- V ly stiff sound transmitting elements;

7 Another obj ectof this invention is to pro- 7 vide a inethod 'and apparatus" for reproduclng soundvibrations whereby a relatively large diaphragm: may i be used 7 Without substantial distortion of the sound Waves 'byreason- 02' I the weight'or ineritiaof such diaphragm.

I Another object of thisinvention is to provide an apparatus for reproducing sound vibrations of the character referred to vvhieh f is of simple and-rugged construction so that drawings are forpurposes of illus; u. only, and are not to be construed as a defi- "otherwise placed" in vibrat S1011 of the variable pressures, l

it is practicable for commercial production and not likely to get out of repair under the conditions'of normal use of such machines.

Other objects Will appear as the description of the invention proceeds.

The invention is cap-able of. beingcarried 7 out'in a variety of ways and of being enibodied in a variety of apparatus, two being shown on the aecompanying drawii. s, but it s to be expressly; understood the tion nition oftli'elimits of theinvention, referencebe ng'had to. the appended claims for that purpose. 7 r

' Reterring in detail to the drawings \vllrrcin thesame reference characters are cinpio wd parts in the sex- 'illustrating,ii1 vertical section, a sound reproducing machine of thecabmet type embodyingthe present invention 'Fig; 2 isa perspective view of a sound re producing machine, of the type adapted to rest upon a table, alsoembodying the present invention; and

Fig. 3is adiagraininatic View illustrating thecomponent elements of sound reproducing apparatus embodying the present invention. V

The method of the present invention involves three major steps The generation of variriie pressures in conformity with soundvibrations, preferably by means of a diaphragm mec iai ically or ion; the transmis- ;y a fluid column, Without substantial ch?" 0 in amplitude, toa second vibratory elm. at, which is preferably a diaphragm ofsubstantiaily the same size as the first diaphragm; and the transmission of the vibrations thereb dnced in said second vibratory element to a diaphragm of a size and character adapted to produce sounds of the desired volume, the transmission of vibrations to thelatter diaphragm'being such as to set into vibration a relatively large body of air Without substantial distortion or loss' of energy.

Asultable'apparatus for carrying out the "method of the present invention is diagrani-v matically illustrated in Fig. 3 and, as here shown, saidapparatus is composed of four ma orelements; V

era-ted pressures, theme-tor M for converting the transmitted pressures into mechanical vibrationaand the amplifier A for converting the'meclianical vibrations ofthe motor intothe acoustical vibrations of a relatively large volume of air.

"The generator G may be of any suitable "construction for converting mechanical vi- The generatorG of the variable pressures, the fllllCl column T for transmitting the genubrations ofsuitable amplitude,[having the periodicities of the sound waveslto be reproduced, into changes ofspressure in a fluid.

column. Saidgenerator preferably employs a diaphragm, whichsmay be of any suitable sizeand character andvib iatedinany suit 7 suitable Way. The power of the motoreifect ing relative movement bemcen the record trace and the stylus isthen thesource of power for creating thechangcs ofpressurc by viln'ation of the diaphragm, and the periodicity and amplitude of such vibrations are determined by the characteristics of the record trace. I I

y The stylus and stylus lever should beso mounted and constructed that the power de- .rivedfrom the relative movement between the record trace and the-stylus is transmitted to. the diaphragm Without substantial loss, of

energy; that is the vibrations imparted to the stylus and stylus lever should be transmitted to the diaphragm ithout substantial lost motion or :flexure, oft-the parts; Also the stylus lever s ould be so connected to the diaphragm and the diaphragm shouldbe of such size and character of construction that the vibrations transmitted thereto by the stylus and stylus lever are received and convertedQinto'chanQesof pressure inthe fluid column engaging the face of the diaphragm Without, substantial lost motion or loss of e y 7 u Thetransmitting element 1 is a tubular element which provides; a-column of fluid, preferably of substantially uniform section throughout; Said column;may be of any suitable length iii-order to transmit the pressure variations created at the generator to a point in proximity to the desired location of the amplifier herein-after described, and said column may be of any suitable cross sections al size and shape. The fluid employed is preferably a gas, and the gas used may be of different kinds and of different pressures, but I prefer to use air at substantially atmospheric pressure, because of the simplicity of construction, smce aleakage between the. interior and exterior of such a column is not accompanied by any loss of pressure or change of gaseous inedium to interfere-with the designedoperation ofthe device. It is to be expressly understood, however,- that; other gases than an may be used if desired,

' With-the large amplifier diaphragm into'viand the gas employed, Whether air or other- Wise,.inay beat other than atmospheric pressure if it is desiredto take advantageof the characteristics of acolumn of gaseous flu d .of ether'desired;pressures;

into changes of pressure in thebor The tubular Wall containing the pressurebe composedof any suitable material, such as metal or glass. transmitting element possesses some of the characteristics of a resonant tube, with a tendencyto accentuate certain periodicities hav- ,ing a definite relation'between their Wave lengths and the length of the tube, said tube,

if desired, may be provided With bendsso as to render the responsiveness of the system to the differentperiodicities more'nearly uniform. By' providing bendsin the tube suitable locations, which form shorter col-.

umns of fluid within the length of the tube, certain pcriodic ties canbe strengthened, and

thereby undue variations in the accentum tion of particular frequencies be avoided.

At 1ts opposite end, said transmitting element T. communicateswith a motor element .M, which may be of any suitable size, shape andconstr'uction. The endot the fluid column at the motor is closed by a vibratory element, preferably a diaphragm of substantially the same size as the diaphragm of generator The variations of pressure transmitted through the column of gaseous fluid are thereby delivered to the diaphragm of the motor hi and thelatter is set into vibracies, and to this end is so constructed astobe relativelystifl and light, and is n'iounted as to offer a mininmniopposition torectilinear movement of the diaphragm as a body.

The vibrations of the diaphragm of the motor M are transmitted to the diaphragm of theampliiier A by a lever, preferably of the second order, the arms of Whichare so proportioned impedance Withthe sound. box impedance, and the load to the available driving pressure; The variations of pressure thus transn'iitted to the diaphragm of the motor are converted Contact with the relatively large area of the amplifier diaphragm under ciniditions which most efficiently set the body of air in contact bration With a periodicity in conformity wlt'lli the periodicity of the vibrations trans: mitted. to the generator diaphragmand with a decreased amplitude-fainl increasedforce As this tubular pressuretowsuitably balance the output transmittingfluid may be of anysuitable cross sectional size and configuration, and

[y of air in V I of operation of the present inventiom'as diagrami ical'ly illustrated in Fig. 3 and above described, maybe embodied in sound reproducing machines of a wide-variety of constructions, two of which are illustrated in Figs. 1 and 2,'bnt it is to be expressly. un-

derstood'that these two figures are intended to illustrate-only two of the many construc tions which may be employed.

In Fig. 1 the invention is shown as our bodied in a sound reproducing or talkingmachine of the cabinet type which is designed to rest upon the floor. A cabinet of any suitable size, shagegmaterial and construction is shown as providodwith a motor board 11 from which is supported a suitable motor '12. A hinged cover 13 of any su table character is illustrated for closing the topof the cab-.

inet Above the motor board 11 a rotatable record support 14 of any suitable construction is designed to carry a record tablet of any suitable character. The reproducing apparatus is illustratedas of that type which isdesigned to cooperate with a laterally undulating record trace, but it is to be expressly understood that the invention can be em- .bodiedfwith equal facility in structures de signed to reproduce other types of record 'traces, V i

lslounted for cooperation with the record.

tablet 15'is the generator G whiclnas-shown in F g. 3, may best sound boxof the type and character heretofore employed for the reproduction of sound records. The casing 16 of said sound box, of any suitable size, shape, construction and material, conta ns a dia- V phragm l7 suitably mounted at its periphery and ci'mn'ected, at or adjacent its center, to a stylus bar 18, which'is mounted in any suitable way for oscillatory movement. Said stylus bar is designed to carry a suitable I needle or stylus 19 for tracking the record trace and converting, with a minimum of lost motion and flexure, the undulations of said trace into vibratory movement of'the diaphragm 17.. 1

Said diaphragm 17' may be of any suitable size, shape, material and construction. I prefer to employ a diaphragm on the order of two and one-half inches in diameter and provided with ,c oncentric, centrally-arranged circular corrugations to give stiffness to the centralportion of the diaphragm, thediaphragm being so constructed at "or adjacent to its periphery as to render the same mar ginally flexible, so that the diaphragm will approximate a piston in the character of its oscillatory movement.

as'g'lass or metal, and having its bore prefer-1 ably of uniform cross section. VVhilet-he cross sectional size of said tube may vary within considerable limits, and may be varied with changes in size of the. cooperating elelinents, I have found that a tube on the order of a half-inch in diameter gives very satisfactory results in the machine illustrated.

Saidtransmission tube '1 of such length and soshaped as to extend to tire desired 10-. cation ofthe relatlvelylargeor amplifying. chaphragm A which, in the form shown in Fig. 1, is disposed in the front wall of the cablnet 10 below the plane of the motor board 11. As shown Silltl. transmission tube T extends rearwardl from the enerator G for a length greater than too radius of the table 14 where it isbent throu h aporoximately'a right angle andextends downwardly'through the motor board 11 toapproximately the vertical height of the center of the diaphragm, where it is again bent at approximatelya right angle and extends horizontally to the motor M.

In order to provide for the relative movement between the generator G and the record tablet 15 a joint is preferably interposed in the length of said tube T, this joint in the form shown providing both for the traverse 0f the generator G across the record tablet 15 and also for the rise and fall of the generator Gr with respect to the plane of the record tablet 15. The joint interposed for these purposes may be of any suitable construction. Inthe form shown the first section 20 of the transmitter tube T is suitably connected to a larbracket 25 suitably attached-to the motor board 11. The interior passages to and through'said tubular extension 24 and tubular bracket common ite w-itl the vertical leg 26 of the transm on tube T extending below the motor board 11, the latter, as heretofore pointed out, communicating with a:

horizontal leg 27 ot said tube which leads to the motor M.

The joint provided by theelements21, 22, 23,24, 25, therefore enables the generator G to swing radially across 'therecord tablet 15 from one extremity of the record trace to mounted, ll

7 in the soundbox casing the other, and also have the desired extent of moven'lent 111 vertical planes. The passage through the joint elements is preferably ,of'

such siz as to constitute"Substantially n9 obstruction or enlargement of the passage through the remaining sections ofthe transmission tube T. v r The moto'r llflvith which the extremilyof the transmi 'on tube T communicates, in cludesa casiu 8, of anyw'niitable shape, construction. in l 29, of any suitable shape, :size, construction and material, but pref-,- ely having substantially the samearea exposed to the fluid withas that of the diaphragnil'l. As a ma exact duplicate of the diaphragm 17.

other suitable sound controlling or modifytrig-elements, is the relativel lar elamolifie'r diaphragmA, which also may be ofrany suitable size, material, shape and construction. I )ref rably construct. thisv diaphragm 0f librousn'iaterial, on the orderof eight to ten inches indiameter, and inlthe manner disclosed and claimedi-n my application 1 Serial No. 130,662, filed August .21, 1926, and en;

titled Diaphragms. As illustrated, said dia-- phragm is composed or .a relatively stificonical central portion fio,having its projected radius approximately one-half the projected radius of the vibratory portion of the entire diaphragmn This conical central portion possesses the advantage of giving maxm'inm' rigidity with minimum weight. .The conical central portion is connected in 'anysuitable way to a corrugated or pleated annular section 31 which at its periphery is suitably at-., tached to aperipheral ring 32 of highly flexible material by'wh ch. said diaphragn'i; may

be mounted and which affords a minimum of resistance to the rectilinear or vibratory movement of the diaphragm proper, A diaphragm constructed and mounted in the man ner just referred to is designed to v'ib'ratefas a whole, or to have a piston-like movement,

I particularly at the lower frequencies;

lntm'posed between ampliti A. is'a, suitable mechanical connection for transmitting the vibratory move ments of diaphragm 29 to the diaphragm of.

said'amplifier.., This mechanieal connection preferably takes the form of a lever and: i prefer to use a lever of the second order.

This lever, 23%, may be of any suitablecon.

struction, but is preferably relatively inflexible. I Said lever is suitably mounted onjthe casing 28 toprovide for its oscillatorymove ment, being shown as provided with a leafwithin u'hichjis 1y suitable way, a diaphragm H er. offact the dia phragm 29 may be, and preferably is, an,

Mounted within or opposite to an aperture.- of suitable size and shape in the front wall of the cabinet 10, which opening may be closed by one or more doors, grills, shutters or any,

the diaphragm of the motor M and the d aphragm 30, 31 of the spring extension 35 which is suitably attached to the casing 28.. At its outer extremity lever 34e is connected to the diaphragm 29, centrally of the latter, by a suitable connect.- mgelement 3t, and intermediate its length said lever Blis connected to the center of the cone by asuitable connecting element 3?, T he distance ofthe connectingelement 37 ",from the fulcrum 35 of said lever 34 is so proportioned tot-lnidistance of the connectini element. 36 from said fulcrum 35 that.

tholoadon the diaphragmis properly balanced with-the" driving pressures transmitted t eto through the system heretofore descr bed or, in other words, so as to balance theoutputimpedance of the amplifier diaphragm with the input impedance of the gen erator G; The amplitude of motion imparted to the amplifier diaphragm from the motor diaphraginis thus decreased, but the total aressureor force acting on the amplifier diaphragm is proportionately increased, so that the amplifier is able to set into vibration a relatively large volume of air which is capable of producing the desired volume of sound Fwithout further amplification;

The motor -M is supported in operative relation to the amplifier A in any suitable way.

lathe form shown a spider-or bracket composed o'f a' plurality ofarms 38 is suitabl-y mounted, at'theentremities of itsarms, on posts or blocks 39 around the opening for the amplifier A, and said bracket at its cen tral portion is provided with a generally circular housing i0 wh ch receives the motor M or constitutes the casing for the'motor diaphragm 29. i

In the embodiment of the invention in 2 the casing 41 for the sound shown repro ducing machine is of smaller size, being ofthe character generally employed for chines designed to" rest on a table or other convenient support, and is provided with a suitable cover- 42 for gaining accessto the sound reproducing mechanism Within the same. As in the embodiment of Fig. 1 the generator G communicatesthrough a long I tube T witha motor Mwvhich .is connected ,elementsQl, 22, 23, 24, 25', and the motor M;

i In operation, the generator Grv traverses the record tablet 15 and the stylus 19 is vi brated by the undulations. ofthe. record trace. lhe vibrations of said stylus are transmitted through thestylus lever 18 to the. diaphragm 17, the vibrations ofsaid diaphragm being converted into changes of 'pi'essure in the decreased amplitude andlincreased force, so

fluid column which is incontact with the rear of the diaphragm 17. The changes of pressure thus generated in the flu d column are transmitted by the latter, through the length of transmission tube T, and inasmuch as said tube is of substantially uniform cross section throughout, these changes of pressure are transmitted, without any substantial change ofperiodicity or amplitude, to the motor diaphragm 29. The motor diaphragm 29 isrset into vibration byithe changes in pressure transmitted'through the tube T, and as in the preferred embodiment said diaphragm 29 is of the same effective areaas the diaphragm l'fl-the vibrations of thefdia= p'hragm 29 are of substantially. the same periodicity and amplitude as the vi rations of the diaphragm 17. i The vibrations of diaphragm 29 are then transmitted-to the relatively large amplifier diaphragm A, and where the connection between said dia phragms is of the preferred construction described and illustrated, the vibrations of the diaphragm 29 are transmitted to'the amplifier diaphragm without lostinotion, but with that said amplifier diaphragm sets a relatively large volume of air in contact there- 3 with into vibratory movement with the same being accurate and faithful reproductions of the sounds recorded in the undulations of the record trace. r i V It will therefore'be perceived that I have provided a sound reproducing machine which is adapted to reproduce soui1dwvith the desired volume from a relatively large diaphragm without introducing thedifliculties heretofore experienced with, the useof large diaphragms, without imposing any uudue burden or wear upon the reproducing stylus and record trace, and without the use of transmission mechanism whose weight or inertiaor vibratory periods are calculated to interfere with the accuracy and efficiency 'of the transmission of the vibrations.

At the same time the transmission of viln'a-tions by variations of pressure in a fluid column has been utilized without introducing the difiiculties incident to the use of a column-of liquid. By USll'lgttlI' at atmospheric pres sure, as in the preferred embodnnenhthe -weight of the movable parts can be main-' tained at a suitable value and, at the same time, expensive constructioii'has been avoid ed because it"is not essential thatthe fluid column be hermetically sealed-since any slight leakage between the fluid column and "diaphragm may at times tend to produce.

F or example,- a sustained note of approx} mately the natural period of the amplifier diaphragm may cause said diaphragm, owing to its inertia, to react on the reproducing in,- strumentalities cooperating with the record tra'ceand produce what isknown asa blast, 'if the large diaphragm is rigidly connected to the reproducing instrumentalit-ies, either through mechanical connections orthrough a relatively rigid body of liquid. In a structure bullt ni'conformity' with the present invention, however, theelasticity and relative compressibility of the, column of gas enables anysuch tendency produced by the amplifier diaphragm to be absorbed within the transmitting column, and the production of blasts is thus minimized if not entirely eliminated.

Moreover, it will be perceived that a methodand apparatus have been provided whereby sounds of the desired volume may be radiated without the use of a horn or sound amplifying mechanism other than a relatively large diaphragmand that owing to the manner in which the'vibrations are transmitted to said'diaphragm, the sounds radiated from said diaphragm are faithful and accurate reproductionsof the sound recorded by the recordtrace." This method and apparatus for transmitting the sound vibrations enables the relatively large diaphragm to be positioned at any suitable distance remote from the instrumentalities for tracking the record trace without introducing inertia effects of relatively heavy or relatively stiff sound transmitting elements or the deleterious effects arising from the natural periods of vibration of such sound transmitting elements. The large diaphragm faithfully reproduces sounds of low periodicity as well as sounds of higher periodicities. The apparatus is also of simple and rugged construction that is practicable for commercial production, is not likely to get out of repair under the conditions'of normal use, whileit is of a character which can be embodied in machines of present commercial sizes andreadily adapted to various sizes and styles of constructions.

It is to be understood thatthe sizes and shapes illustrated are only exemplary, as

changes may be made within considerable limits in the size or proportioning of parts Without departing from the spirit of the llll variations in the source of power.

the transmission system. y

The length and'shape of the fluid column may be varied W thin very ide limits de-- c periooicities.

present, invention. The total power which can be generated is determined by the record trace having undulations of predetermined amplitude and the speed at which said record trace movespast the reproducing stylus. The

load is determined byathe large diaphragm.

of predetermined area andweight which is sub3ected' to a predetermined pressure. Y As the iiower available is varied by different speeds oi rotation or by dltl'erent amplitudes of record trace, there is more or less; power which can be put to Work and thereiore the load which can be moved, that is the sizeand character of diaphragm, Willvvary with the rial-Lions will be accompanied by variations in the sizes and proportions of the'pa-rts' oi pending upon the'desired location of the amord track; 7 and character ofthe machine asa WllOlG.. I

- have found it desirable to introduce bends:

into this fluid coh'unn and to so 1: osition said bends as to tend tosmooth out the response curve of the transi'nission system.v As heretofore pointed out" the transmission tube T; partakes of some of the characteristics oia resenant tube, so that certain periodicities arc accentuated toa greater-extent than other I have "found that by determiningthe characteristics of thesystem Without bends and noting the irregularities in the curve of i.ntensities of sound at various, periodicities, the ma or irregularities in said curve maybe smoothed out by so: positioningthe'bends as to accentuate periodicities which tendto be weak or to Weaken periodicities which tendrto be over-strong. Each bend in the tube provides a" reflecting surface so that a fluid column. is'tormed from the bendand having a natural periodicity of its own. By

- making th se columns measured '7 from the,

heads (if-lengths suitable toaccentuate given poi-i engiven reriod-icities and make the responsiveness of the system more nearly unitorn'n The character or? t-helever employed between the motor diaphragm and theamplitier diapli-ragym may be varied, and. the pro- [)Ul'iI-lOlllllg of the arms of said lever will n of the ma-.

w y with changes in the dc- 1c.- 'll-hc arms oi: this levershouldbe so "h v proportioiiedthattahiug into c. msideration the power derivable from the actuation of the record tracking instrun'ientalities and: the

' relatively large diaphragm oW-i to its load or resistance to vvibration exist-i at the 7 area, the amplitude 1 of vibration; is decreased and the force formoving the relatively large diaphragm is so increased that the latter dia-,

phragm is efficiently setinto vibration without substantial distortion to produce sounds Such va-v faithful reproduction o? sound of thek diaphraginwith respect: to the rec- 1g instrumentahties'and the size dicities it becomes possibleto strength ofu-the desired volume with ia'thtul-nessaml en iciency. I have found that by use of the present "invention the power derivablefrom the standard talk ng machine record, when rotating at the speed now conventionally used, is capable o1 setting; a. diaphragm on the orderoitnine inches in diameter into vi l'i'rzition; so astoproduce sounds oi substantially the same volume as that produced by i-itandard: ina iims-l but without he ui -aeolt a horn *or ,otl

the arms of said lever: Wil 1 vary with the s e and character otthe dia'rhragnis, and to: any given design itis desirable to as i "n the point of connection of said l it) the amplifier diaphrr n which" produces tl most pleasing efi'ects,,tliat is gives the mo struction. arrangement and proportion of parts, and certain features used Without ther features Without degarting from thespirit of this invention. 1

VVhile itis pref-erred to employ a gaseous fluid as the transmitting mediuim some of the advantages of the invention can be obtained-With liquid asrthe transmitting medium, butas this requires a generator, transmitt-ing element and motor that are fluidtight, as Well as involves other disadvantages inherent inthe use of a liquid, the useof fluid column of preferably air preferablefor reasons heretofore pointed out.

Referenceis therefore to'be had to the uppended claims for a definition of the limits of the invention. In said claims the expression sound Waves of relatively'large volmne .isen'l'ployed to mean sound waves of thevolume usually produced by s undieprjoduciu'g machines by the employn'icut' of a horn, ,or otheramplifying mechanism and the expression relativelylargo diapnragm is-used to mean a diaphragm of a size onthe order of that appropriate for generating: sound; of the desired volume without the no cessity of use" otsupplemental amplifying means. 7

hat is claimed is 1. The method of generating sound: waves of relatively large volume which includes producing variations of fluid pressure in conamplifier. l irci'er to use 2rclever ofsuus illy'i'he character illus trated outhe the .ng, but theproportonot v is diaphragm, transmitting said. generated pressures to a. second diaphragm, and mechanformity with the periodicities of the sound waves to be reproduced, transmitting said variations of pressure to a motor wherein said changes'of pressure areconverted into mechani'calvibrations, and mechanically transmitting the converted vibrationsto a rela tively large diaphragm adapted to generate Y sound waves oftlie desired volume NiltllOllt further amplification, 1 v 3 2. The method of generating sound Waves of relatively large volume whichiincludes vibrating a diaphragm in conformity with the periodicities of the sound waves to be reproduced, creating changes of pressure inacolumn of gaseous i iuid by the vibrationof said ically transmitting the vibrations induced in relativelylarge hrea. s

8. The method of generating sound waves of relatively large volum'e'which includes vibrating a diaphragm to create variations of pressure in a fluid column in'contact therewith, transmitting said changes of pressure in said fluid column to a second diaphragm said second diaphragm to a diaphragniof to produce therein vibrations of substantially the same periodicityand amplitude as those of the first diaphragm, and converting the vibrations of said second diaphragm into v brations of the same periodicity but of d1frerentamplitude' in a relatively large diaphragm.

' 4. The method of generating sound waves of relatively large volume which includes oreating in a relatively long column of gaseous fluid changes of pressure in conformity with the periodicities of the sound Waves to be reproduced, transmitting said changes of pressure without substantial change in amplitude to a motor element, and transmitting the vibrations thereby produced in said motor element to a-Jrelativ'ely large dia )hragm'.

5. The method of generating sound waves of relatively large volume which includes'vi brating a diaphragm in conformity with the sound Waves to be reproduced, transmitting changes of pressure of substantially the same frequency and amplitude as the vibrations of said diaphragm" through a relatively long column of gaseous fluid, converting the transmitted chan es of pressure into mechanical vibrations of substantiallythe same periodicity and amplitude as those of the lirst dia phragn'i, and transmitting said mechanical vibrations vith the same periodicity but of a different amplitude to a relatively large diaphragm. s t p 6. The method of generating sound waves of relatively large volume which includes vibrating a diaphragm in conformity with the sound waves to be reproduced, converting the vibrations of said diaphragm into changes :of pressure in'a relatively long col umn of gaseous fluid, converting thecha-nges of pressure transmitted by said fluid column into mechanical vib 'ations of substantially the same amplitude and periodicity as those of the first diaphragm, and mechanically transferring said last-named vibrations to a relatively large diaphragm.

7 The method of generating sound waves of relatively large volume which includes vi brating adiaphragm in conformity with the sound Waves to be reproduced, converting saidvibrationsinto changes of pressure in a relatively long column-of gaseous fluid in contact with said diaphragm, converting said changes of "pressure. into mechanical vibrations of a second diaphragm, and transferring said mechanical vibrations to a relative- 1y large diaphragm. I

8. The method of generating soundwaves of relatively large volume which includes producingvariations of pressure in conformity with the'periodicitv of the sound waves to be reproduced, transmitting said variations of pressure through a aseous fluid to a motor wherein said changes of pressure are converted into mechanical vibrations of substantially the same amplitude as the initial variations of pressure, and mechanically transmitting the converted vibrations to arelatively large diaphragm.

9. The method of generating sound waves of relatively large volume which includes.

, waves to be reproduced,"transinitting said va riations of pressure through a static column of gaseous fluid to a motor wherein said changes of pressure are converted into mechanical vibrations, and mechanically transmitting the converted vibrations to a relatively large diaphragm.

11. The method of generating sound waves of relatively large volume which includes vibrating a diaphragm in conformity with the periodicity of the sound waves to bereproduced, creating changes of pressure in a column of fluid by-the vibration of'said diaphragm, transmitting said generated pressures Without substantial change of amplitude to a second diaphragm, and transmitting the vibrations induced in saidsecond diaphragm to a diaphragm of relatively large area.

12. The method of generating sound waves of relatively large volume which includes viof relatively large volume whichincludes vibratinga diaphragm to create variations of I pressure in a column of gaseou's fluid in con- 7 tacttherewith, ,transmittingsaidchanges of pressure in said fluid Y column without substantial change of amplitude to a second diaphragm, and mechanically transmitting the vibrations oi saidsecond diaphragm with decreased amplitude and increased force to a relatlvely large diaphragm.

14 The method of generating sound waves of relatively large volume which includesv vibrating adiaphragmto create variations of pressure in a fluid-"column, transmitting said changes of pressure w thout substantial change n amplitude to, a second diaphragm,

.and mechanically transmitting the vibrations of said second diaphragm to a relatively large diaphragm. 1 I V 15. Themethodo'f generating sound waves oi relatively large volume .which includes vibrating a diaphragm to create Variations of pressure inacolumn of gaseous fluid, transmitting said changes of pressure without substantial change in amplitude to a second, diaphragm, and mechanically transmitting the vibrations oi said second diaphragm to a relatively large. diaphragm adapted to generate sound waves of the desired, volumes without further amplification.-

16.; In soundreproducing apparatus, thecombination of a. diaphragm, a second dia-v phragm, means providing a column of, gaseous fluid extending between said diaphragins, "a diaphragmlarge relative to saidflrst two, diaphragms, and a mechan cal connection between said second and said large diaphragm.

17. In sound reproducing apparatus, thew combination of a diaphragm, a second-diaihra 'm means Jrovidin a relativel .lon

b 7 h v 2'3 column of gaseous. fluid of relatively small cross section extending between saidjdiaphragms, a relatively large diaphragm, and

. amechanical connectionbetweenjsaid second and said large diaphragms, p

18. In sound reproduc ng apparatus',;the

combination of a diaphragm, a second diaphragm, meansv providing a column of fluid.. extendlng between said 'diaphragms, a relativel lar e dia 'hra m and a lever connecb D tion between said second and saidlarge diaphragms.

I 19. In sound reproducing. the

: a lever of the: second order between said 1 vibrations,

combination of a diaphragm,a second dia- ;ph'ragm, means providing a column of fluid extending between saiddiaphragms, a relatively large diaphragm, and a leverconnection betweensaid-second and said large diaphragmsadaptedj to transmit vibrations of: decreased. amplitude. and increased force. .to saidlarge. diaphragm.

20. In soundreproducing apparatus, the combination of a diaphragm, means providing a column of fluid in contact with said diaphragm, a second diaphragm having the same area exposed to saidfluid column assaid first diaphragm," and -'a relatively large diaphragm vibrated by said second diaphragm. 21. In sound reproducing apparatus, the combination of a diaphragm, means. providingca column of fluid in contact with said diaphragm, a second diaphragm having the same area exposed-to saidfiuid column as said Qfir'st diaphragm, and a. relatively. large diaphragm connected to said second diaphragm.

'22.,111 sound. reproducingv apparatus, the combination of a diaphragm, means providing a column of fluid in contact with saiddiaphragm, aseconddiaphragm having the same area exposedto said fluid column as said'first diaphragm, a relatively large diaphragm, and a lever connection between said second and .saidlarge diaphragms. I

23. In sound reproducing apparatus, the combination of a diaphragm, means providing a column of fluid in contact with said diaphragm, asecond diaphragm having the same areaexposed to said fluid column as saidfirst diaphragm, a relatively large diaphragm, and

sec-

ond and saidlarge diaphragms. I 1

24. In sound reproducing apparatus, means for producingin ;a' static column er. gaseous f fluidvariations] of pressure in conformity with soundvibrations,.means in operative relation to saidcolumn of fluid for converting the pressure changes n said column nto me.- chan cal .vibratlons, a I'Ql2tt1VBly large diaphragm adapted to generate sounds of the desired volume without further amplification, and means for transferringv said mechanical vibrations to said large diaphragm. I

25. In sound reproducing apparatus, means for producing in astat'ic column of: fluid variations of pressurein accordance with sound vibrations,emeans inoperative relation to said columnof fluid for converting the pressurejcha'nges in sa d column into mechanical vibrat ons, I arelatlvely large diaphragm, and

- means for. transferring said mechanical vibrations to,

aid large diaphragm with decreased .amplitudeiand increasedforce, v

26. In sound. reproduclng apparatus, means for producing in a static column of fluid vari .ations of pressure in accordance with sound means exposed to said column of fluid and adapted to be vibrated thereby'fwith substantially the same amplitudeas saidfirstgaseous fluid for transmitting variations of named means, a relatively large diaphragm,

and a lever for transferring the vibrations of said last-named means to said large diaphragm.

27. In sound reproducing apparatus, the combination of a diaphragm, means for vibrating said diaphragm in conformity with sound waves, means providing a relatively long column of gaseous fluid for transmitting variations of pressure produced by the vibrations of said diaphragrma second diaphragm vibrated by the changes in pressure in said largediaphragm connectedto said second diaphragm.

29. In sound reproducing apparatus, the combination of a 'diaphragm, means for vibrating said diaphragmin conformity with sound waves, means providing a; column of pressure in conformity with the frequency and amplitude of the vibrations of said diaphragm, a seconddiaphragm'vibrated by the changes of pressure in said fluid column, and

' a diaphragm large relative to said first two diaphragms and vibrated by saidsecond diaphragm. H V I 30. In. sound 7 reproducing apparatus, the

combination .of a diaphragm, means for v1 brating said diaphragm in conformity with sound waves, means providing a column of fluid for transmitting variations of'pressure in conformity with the frequency and amplitudeof the vibrations of said diaphragm, a second diaphragm vibrated with substantially the same amplitude'as said first diaphragm' by the changes of pressure in said fluid column, and a relatively large diaphragm vibrated by said second'diaphragm'.

I 31. In sound reproducing apparatus, the combination of a diaphragm, means for 'vibrating said diaphragm in conformity with soundfwaves, means providing a column of gaseous fluid forfltransmitting variations of pressure,a.'second diaphragm'of substantially the same area as said first diaphragm vibrated by the changes ofpressure in said fluid column, and a relatively large diaphragm vibrated by said second diaphragm,

32. In sound reproducing apparatus; the combination of a diaphragm, means for',vi-

brating said diaphragm in conformity with sound waves, means providing'a column of gaseous fluid for transmitting variations of pressure in conformity with the vibrations of said diaphragm, a second diaphragm vibrated 'by the changes of pressure in said fluid, a relatively large diaphragm, and a lever between said second diaphragm and said large diaphragm. I

33. In sound reproducing apparatus, the combination of a diaphragm, means for vibrating said diaphragm in conformity with sound waves, means providing a column of gaseous fluid for transmitting variations of pressure in conformity with the vibrations of said diaphragm, a second diaphragm vibrated by the changes of pressure in said fluid column, a relatively large diaphragm, and means for transmitting the vibrations of said second diaphragm to said large diaphragm with decreased'amplitude and increased force.

34. In sound reproducing apparatus, the combination of a diaphragm, means for vibrating said diaphragm in conformity with sound waves, means providing a column of gaseous fluid for transmitting variations of pressure in conformity with the vibrations of said diaphragm, a second diaphragm of substantially the same size as said first diaphragm and vibrated by the changes of pressure in said fluid column, "a relatively large diaphragm, and means for transmitting the vibrations of said second diaphragm to said large diaphragm with decreased amplitude and increased force.

35. In sound reproducing apparatus, means for producing in a static column of fluid variationsof pressure in accordance with sound vibrations, means in operative relation to said columnof fluid for converting the pressure changes in said column into mechanical vibrations, a relatively large diaphragm adapted to generate sounds of the desired volume without further amplification, and means for transmitting said mechanical vibrations to said large diaphragm;

36. In sound reproducing apparatus, the combination of a diaphragm, means for vibrating said diaphragm in conformity with sound waves, means providing a column of gaseous fluid for transmitting variations in pressure in conformitywith the vibrations of said diaphragm, a second diaphragm of substantially the same effective area as said first diaphragm and vibratedfby the changes of pressure in said fluid column, a relatively large diaphragm adapted to generate sound waves of the desired volume without further amplification, and a lever between said second diaphragm and said large diaphragm.

37. In sound reproducing apparatus, the

combination of a diaphragm, means for vibrating said diaphragm in conformity with sound waves,.means providing a relatively long fluid column-of substantially uniform cross section for transmittlng variations in pressure-in conformity with the'vibrations of and said large diaphragm whereby. the total pressure on said second diaphragm is amplifled and transmitted to said large diaphragm.

39. In sound reproducing apparatus, the combination of a diaphragm, means providing a column of gaseous fluid in contact with said diaphragm, a second diaphragm subjected to said fluid column, said fluid column and second diaphragm being adapted to transmit changes of pressure without amplification, a relatively large diaphragm, and a connection between said second diaphragm and said large diaphragm adapted to amplify the total pressure acting on said second diaphragm.

10. In sound reproducing apparatus, the combination of a diaphragm, means for vibrating said diaphragm in conformity with sound waves,

gaseous fluid for transmitting variations oi:

. brating said diaphragm in sound waves, means providing a relativelyv fluid of relatively for transmitting variapressure, said means being provided with ends to prevent undesirable diflerences in accentuation of notes by the action of said column, a second diaphragm vibrated by the changes of pressure in said fluid column, and a relatively said second diaphragm.

41. In sound reproducing apparatus, the combination of a diaphragm, means for viconformity with long column of gaseous small cross section tions of pressure, a second diaphragm in contact with said fluid column and having sub stantially the same area exposed to said fluid column as said first diaphragm, and a rela-' Sec-i combination I with p a record I support, I a diaphragnn'mea'ns for vibrating tively large diaphragm vibrated by said 0nd diaphragm.

42. In a sound reproducing machine, in:

combination with a record support, a diaphragm, means from a record on said support, means providing a relatively long column of gaseous in contact with said diaphragm, whereby said column, diaphragm and phragm vibrating means may traverse said record support, a second diaphragm subjected to the variations of pressure in said fluid column, and a relatively large diaphragm connected to said second diaphragm.

with said fluid 1 bevibrated'by fluid column,

relatively large means providing a column oflargediaphragm connected to fluid column, atively'large diaphragm in the=wall of said joint intermediate said large diap'hiagm "to said record sup ora for vibrating said diaphragm fluid 4 amounting dia 0P I said elements,-a relatively; large diaphragm in the wall of said cabinet, a lever between said second diaphragm and said large diaphragm, and a joint ressure In a sound'reproducing machine, in

combination with a record 'support',a diaphragm, means forvibrating said diaphragm from a record on'=-said support, means providinga column of gaseous fluid in contact with said diaphragm, means intermediate the length of said column providing a joint for relative movement between said diaphragm and 'said record support, a second diaphragm having substantially the same area in contact column as said first diaphragm, and a relatively large diaphragm vibrated by said second diaphragm.

lL-Inf-a sound reproducing machine, in combination with a record support, a diaphragm, means for vibrating said diaphragm from a record'on said support, means providing-a fluid column in contact with said "diaphragm, a second diaphragm adaptedto the-changes ofp'ressure in said'r'c.

"a'cabinet for said elements, a diaphragm in the wall of said cabinet, and connections between said second diaphragm and said large diaphragm.

45.1In a sound reproducing machine, in

combination with a record support, adiaphragm, means for vibrating said diaphragm from a recordon said support, means providing a column of'ga'seousfluid in contact With said diaphragm, a second diaphragm "adapted to be vibrated by the changes of pressure 'in said fluid column, a cabinet for'said 'elements,a relatively-large diaphragm in the wall of said cabinet, and a lever'between said second diaphragm and said large diaphragmw" 5&6. In a sound reproducing machine, in

' combinationwitha record support, a diaphragm, means for vibrating said diaphragm from agi'ecor'd on said support, means providinga coluinn'offluid in contact with said diaphragm, asecond diaphragm adapt-ed to be vibrated by the "changes of pressure insaid a cabinetfor sa delements, a relcabinet, a connection between said second d1 1 'aphragin 'and said largediaphragin, and a v and said .tfirst named ,diapliragm' whereby said first-named diaphragm may move relatively 47'. In a sound reproducing machine, in

said diaphragm I from a record on said support, means provide,

column of fluid in contact with said dia phragm, a second diaphragm of substantially the same area as said, first diaphragm and adapted to 'bevibrated by thev changes; of

a cabinet 011.;

in said fluidcolumn,

between said second diaphragm and first diaphragm whereby said first diam;

. produce,

combination With a and means including a .bratile diaphragm phragm may move relatively to said record support. r

48. In a machine for reproducing sound Waves from a record of the same, a vibratile diaphragm of largevarea supported at its periphery and freely exposed to unconfined air,

fluid column transmission device through Which the vibrations produced by the record are transmitted to the diaphragm, the diaphragm being of sufficient area to impartto the surrounding free .air sound Waves substantially corresponding in volume to the recorded sound Waves.

49. In a sound regenerating machine, a vibratile diaphragm of large area supported at its periphery and freely exposed to unconned air, a sound-vibrated element, and means including a fluid column transmission means connecting said element and said diaphragm and arranged to impart to the diaphragm vibrations Which are of less amplitude than the vibrations imparted to said element- 50. In a sound regenerating machine, a visupported at itsperiphery to unconfined air, a soundand freely exposed and means including a i vibrated element,

fluid column transmissionmeans connecting said element and said diaphragm and arranged to impart to said diaphragm vibrations which are of less amplitude than'the vibrations imparted to said element, said diaphragm having an area sufliciently large to] without further amplification, sound Waves of large volume and carrying power. a

51. In a sound reproducing machine, in

record support,la diaphragm, means for vibrating said diaphragm from a record on said support, means providing. a relatively long column of gaseous fluid in contact with said diaphragm, means intermediate the length ofsaid columnrprovi'ding a joint for movement, of said dia-- phragm toward andfawayfrom said support, a second diaphragm subjected to the variations of pressure in said fluid column, and a' relatively large diaphragm connected to said second diaphrag In a sound reproducing machine, in

combination with a phragm, means 'phragm from a record on said support, means providing a relatively long columnof gaseous fluid in contact with said diaphragm, a second diaphragm of substantially'the same record support, a dia-H effective area as said first diaphragm and.

subjected to the variationsiof pressure lnsaid uid column, a relatively large diaphragm connectedto said second diaphragm, and a joint in said fluid column intermediate said first and said'second diaphragms.

In-testimony whereof "I have signed this 7 WILLIAM DQLA RUE. I i r, "V

specification.

for vibrating said; dia- I 

